JPH08166166A - Hot air heater - Google Patents

Abstract

PURPOSE: To maintain the concentration of nitrogen oxide in air within a room to be heated at a proper position by detecting the concentration of the nitrogen oxide in air in a room to be heated to adjust a ratio (air/fuel ratio) between a supply value of air for combustion and a supply value of a fuel with respect to a burner based on information detected. CONSTITUTION: In a hot air heater, a combustion block F containing a gas burner G or the like is arranged within a casing 23 which has a hot air blowoff port 21 formed at a lower part of a front wall thereof and an air suction port 22b on a rear wall thereof. A part of air of a room to be heated sucked is supplied to the gas burner G while a sirocco fan 24 is provided blowing a mixed gas, mixing a combustion gas generated with the rest of the air, to the room to be heated from the hot air blowoff port 21. In this case, an NOx sensor N is provided to detect the concentration of NOx in the air of the room to be heated and when the concentration of the NOx determined exceeds a allowable set value, a proportional value or the like of a fuel supply system is controlled for a higher air/fuel ratio to reduce the amount of a fuel gas to supply below an initial value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention supplies a burner and a part of the air in the heating target room sucked from the suction port to the burner as combustion air, and the rest is mixed with the combustion gas produced by the burner. Then, the present invention relates to a warm air heater provided with ventilation means for ventilating the air-fuel mixture from the air outlet to the heating target room.

[0002]

2. Description of the Related Art In such a warm air heater, conventionally, a CO sensor for detecting the CO concentration in the combustion gas produced by the burner is provided, and the combustion air supply amount to the burner ( The air-fuel ratio indicating the ratio (Ia / Ig) between Ia) and the fuel supply amount (Ig) is adjusted. And CO in the air of the room to be heated
The concentration was maintained at an appropriate level.

[0003]

By the way, in the combustion gas produced by the burner, in addition to CO gas, nitrogen oxides such as NO gas and NO ₂ gas, which pose a problem in terms of air pollution, are contained. However, in the conventional hot air heater, although consideration is given to maintain the CO concentration in the air in the heating target room in an appropriate state, the concentration of nitrogen oxides in the air in the heating target room is considered. There wasn't.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a hot air heater capable of maintaining the nitrogen oxide concentration in the air in the room to be heated in an appropriate state. Especially.

[0005]

The first characteristic configuration of the warm air heater according to the present invention is in the air in the room to be heated, or
In the generated combustion gas, or a nitrogen oxide sensor for detecting the nitrogen oxide concentration in the air-fuel mixture, based on the detection information of the nitrogen oxide sensor, the combustion air supply amount and fuel supply amount to the burner The air-fuel ratio adjusting means for adjusting the air-fuel ratio indicating the ratio of

A second characteristic configuration is that the air-fuel ratio adjusting means adjusts the air-fuel ratio based on the detection information of the nitrogen oxide sensor so as to maintain the nitrogen oxide concentration below an allowable set value. It is configured as follows.

A third characteristic configuration is that the air-fuel ratio adjusting means sets the nitrogen oxide concentration to a value equal to or less than a set value determined according to the combustion amount of the burner based on the detection information of the nitrogen oxide sensor. It is configured to adjust the air-fuel ratio so as to maintain it.

A fourth characteristic structure is provided with fuel supply amount adjusting means for adjusting the fuel supply amount to the burner, and the air-fuel ratio adjusting means controls the fuel supply amount adjusting means. It is configured to adjust the air-fuel ratio.

A fifth characteristic configuration is based on that the air-fuel ratio adjusting means controls the ventilation amount of the ventilation means.
It is configured to adjust the air-fuel ratio.

A sixth characteristic configuration is that the nitrogen oxide sensor is provided in the main body so as to detect the nitrogen oxide concentration in the air sucked from the suction port.

[0011]

According to the first characteristic configuration, the nitrogen oxide sensor detects the nitrogen oxide concentration in the air in the heating target chamber, in the generated combustion gas, or in the air-fuel mixture,
By the air-fuel ratio adjusting means, based on the detection information of the nitrogen oxide sensor, so as to maintain the nitrogen oxide concentration in the air of the room to be heated in an appropriate state, the combustion air supply amount and fuel supply amount to the burner The air-fuel ratio indicating the ratio of is adjusted. By the way, in the case of detecting the nitrogen oxide concentration in the produced combustion gas or the air-fuel mixture by the nitrogen oxide sensor,
Since it is possible to know the generation status of nitrogen oxides from the burner, if the amount of nitrogen oxides generated from the burner becomes higher than usual, quickly adjust the air-fuel ratio to return to a normal state. It is possible to make it preferable. However, even if the amount of nitrogen oxides generated from the burner increases, if the volume of the heating target chamber is large, the nitrogen oxide concentration in the air of the heating target chamber may not reach an inappropriate state. However, in such a case, the air-fuel ratio will be adjusted unnecessarily. Further, in particular, when the nitrogen oxide sensor detects the nitrogen oxide concentration in the produced combustion gas, the nitrogen oxide sensor is exposed to a high-concentration nitrogen oxide atmosphere and a high-temperature atmosphere. There is a drawback that the nitrogen oxide sensor deteriorates quickly. On the other hand, when detecting the nitrogen oxide concentration in the air of the heating target room by the nitrogen oxide sensor, the air temperature of the air in the heating target room is reflected in the empty state. Since the fuel ratio can be adjusted, unnecessary adjustment of the air-fuel ratio can be avoided. Further, since the nitrogen oxide sensor is not exposed to the high-concentration nitrogen oxide atmosphere and the high temperature atmosphere, deterioration of the nitrogen oxide sensor can be suppressed.

According to the second characteristic configuration, by maintaining the nitrogen oxide concentration in the air in the room to be heated, in the produced combustion gas, or in the air-fuel mixture below the allowable set value, It is possible to maintain the nitrogen oxide concentration in the air in the room to be heated in an appropriate state below the allowable value. Incidentally, the allowable set value is, when measuring the nitrogen oxide concentration in the air of the heating target room, when measuring the nitrogen oxide concentration in the generated combustion gas, and the nitrogen oxide in the air-fuel mixture Set for each case of measuring concentration.

The operation of the third characteristic structure is as follows. In order to maintain the temperature of the room to be heated at the target set temperature, the burner combustion amount is adjusted, but according to the combustion amount,
The amount of nitrogen oxides generated is different. Therefore, in the case where the set value is uniquely determined regardless of the burner combustion amount, and the air-fuel ratio is adjusted so that the nitrogen oxide concentration is maintained at the uniquely set value or less, Such a problem occurs. For example, if the combustion amount of the burner becomes larger than the combustion amount corresponding to the uniquely set value, the nitrogen oxide concentration easily becomes larger than the uniquely set value. Then, the air-fuel ratio will be adjusted. In order to avoid such a situation, if the set value is uniquely set for the combustion amount near the maximum combustion amount of the burner, even if the amount of nitrogen oxides generated is higher than usual, for example, In the case where the combustion amount of the burner is small, even if the ventilation amount of the ventilation means becomes smaller than usual and the temperature of the generated combustion gas becomes higher than usual, the nitrogen oxide concentration is uniquely Since the state smaller than the set value is maintained, the air-fuel ratio may not be adjusted. Therefore, if the set value is determined according to the combustion amount of the burner, and the air-fuel ratio is adjusted so as to maintain the nitrogen oxide concentration below the set value determined according to the combustion amount of the burner, the above-mentioned problem occurs. While avoiding, the nitrogen oxide concentration in the air in the room to be heated can be maintained in an appropriate state.

According to the fourth characteristic configuration, the fuel supply amount adjusting means is controlled so that the fuel supply amount to the burner is reduced when the nitrogen oxide concentration becomes larger than an appropriate value. The air-fuel ratio is adjusted to a large value. Therefore,
The combustion amount of the burner is reduced and the generation amount of nitrogen oxides is reduced.

According to the fifth characteristic configuration, the ventilation amount of the ventilation means is controlled so that the combustion air supply amount to the burner increases when the nitrogen oxide concentration becomes higher than an appropriate value. The air-fuel ratio is adjusted to a large value. Therefore, the combustion amount of the burner does not change and the air-fuel ratio becomes large, so that the temperature of the produced combustion gas becomes low and the amount of nitrogen oxide produced becomes small.

The operation of the sixth characteristic structure is as follows. When detecting the concentration of nitrogen oxides in the air of the room to be heated by the nitrogen oxide sensor, it is possible to provide the nitrogen oxide sensor in the room to be heated. When the oxide sensor is provided in the room to be heated, the work of installing the nitrogen oxide sensor and the wiring work for transmitting the detection information of the nitrogen oxide sensor to the air-fuel ratio adjusting means become unnecessary.

[0017]

According to the first characteristic configuration, since the nitrogen oxide concentration in the air in the room to be heated can be maintained in an appropriate state, comfortable heating can be performed, and in addition, in terms of preventing air pollution. It is now possible to provide an excellent hot air heater.

According to the second characteristic constitution, the present invention can be carried out with a simple control constitution in which the nitrogen oxide concentration is simply controlled so as to be maintained below the allowable set value. The cost for doing so can be further reduced.

According to the third characteristic configuration, the nitrogen oxide concentration in the air in the room to be heated can be maintained in an appropriate state corresponding to the combustion amount of the burner.

According to the fourth characteristic configuration, the amount of nitrogen oxides generated can be rapidly reduced, so that the concentration of nitrogen oxides in the air in the room to be heated can be quickly returned to an appropriate state. .

According to the fifth characteristic configuration, the amount of nitrogen oxides generated can be reduced without changing the burner combustion amount. Therefore, the room temperature change of the heating target room can be suppressed while suppressing the room temperature change of the heating target room. The nitrogen oxide concentration in air can be returned to an appropriate state.

According to the sixth characteristic configuration, the present invention can be implemented in a state in which the installation work of the nitrogen oxide sensor and the wiring work for transmitting the detection information of the nitrogen oxide sensor are unnecessary. , It has become possible to install and move the warm air heater extremely easily.

[0023]

Embodiments will be described below with reference to the drawings.
First, the overall configuration of the warm air heater will be described with reference to FIGS. 1 and 2. As shown in FIGS. 1 and 2, a gas burner G or the like is installed in an internal space of a casing 23 in which a warm air outlet 21 is formed in a lower portion of a front wall and two air suction ports 22a and 22b are formed in a rear wall. The combustion block F and a part of the air in the heating target chamber sucked from the air suction ports 22a and 22b are supplied to the gas burner G as combustion air, and the rest is mixed with the combustion gas produced by the gas burner G to form a mixture thereof. A sirocco fan 24 as a ventilation means for ventilating air from the hot air outlet 21 into the room to be heated.
And a control block S in which a control device C for controlling various controls of the warm air heater, a fuel gas supply device D, and the like are installed. Further, the air suction port 22b is provided with a NOx sensor N1 as a nitrogen oxide sensor N for detecting the concentration of nitrogen oxides in the air of the room to be heated sucked from the air suction port 22b, and the outer surface of the rear wall of the casing 23. Is provided with a temperature sensor T that detects the room temperature of the room to be heated. Further, a filter for removing dust is provided at the air intake ports 22a and 22b.

Next, the combustion block F will be described with reference to FIGS. 1 and 2. Combustion gas flow path P for guiding the combustion gas generated by the gas burner G to the hot air outlet 21
Is formed in a reciprocating flow path shape in which the combustion gas is caused to flow upward and then downward by the flow path forming material 25. still,
The flow path forming material 25 connects one opening end portion to the upper opening 1u of the burner casing 1 in the gas burner G so as to communicate therewith,
The other open end is connected to the hot air outlet 21.

An outer peripheral member 26 is provided so as to surround the outer periphery of the burner casing 1 and the flow passage forming material 25, and cooling air is provided between each of the burner casing 1 and the flow passage forming material 25 and the outer peripheral member 26. A reciprocating flow channel-like cooling air flow channel R is formed which causes the liquid to flow upward and then downward. or,
The partition member 27 forms an air supply portion K that communicates with the internal space of the burner casing 1 and the cooling air flow path R. The sirocco fan 24 is connected to the partition member 27 so that the air supplied from the sirocco fan 24 is supplied to the air supply portion K. Also, the lower opening 1d of the burner casing 1
Further, punching plates 12 and 28 for rectification are provided at the flow path starting end portions of the cooling air flow path R, respectively.

A plurality of slit-shaped openings 29 are formed in each of the four side surface portions of the flow path forming material 25 which forms the return flow path portion Pr through which the combustion gas flows in the combustion gas flow path P. The slit-shaped opening 29 connects the return flow passage Pr in the combustion gas flow passage P and the return flow passage Rr in the cooling air flow passage R.

A plurality of slit-shaped openings 30 are formed in the side surface of the flow path forming member 25 which separates the air supply part K from the return flow path part Pr in the combustion gas flow path P. That is, the air sent from the sirocco fan 24 is supplied from the air supply portion K to the return passage portion Pr in the combustion gas passage P.

That is, the sirocco fan 24 discharges combustion air into the gas burner G and discharges cooling air into the cooling air passage R to generate from the gas burner G flowing in the combustion gas passage P. Cooling air flowing through the cooling air passage R is supplied to the combustion gas through the slit-shaped opening 29,
In addition, the combustion gas flow path P is provided through the slit-shaped opening 30.
The cooling air is discharged to the return flow path Pr in, and the mixture of the generated combustion gas and the cooling air from each of the slit-shaped opening 29 and the slit-shaped opening 30 is discharged from the warm air outlet 21.

Next, the specific construction of the gas burner G will be described with reference to FIGS. First, the overall configuration of the gas burner G will be described.

Reference numeral 1 in the drawing denotes a burner casing. A central vertical wall 1A is erected at the center of the burner casing 1 in the left-right direction (hereinafter abbreviated as the left-right direction) in a front view so that the inside of the burner casing 1 is provided. There are two burner spaces on the left and right. Then, the burner section A, which has the same configuration for each of the two left and right burner spaces, is arranged in order from the top to bottom in the vertical direction.
A mixed gas supply section B for supplying the mixed gas upward to the burner section A and a mixing section M for mixing the fuel gas and the combustion air are provided. Further, D shown in FIG. 5 is a fuel gas supply device for supplying the fuel gas to the mixing portions M, M on both the left and right sides.

Next, the burner section A will be specifically described. The burner portion A is provided with an ejection portion forming wall body 2 having a substantially V-shaped vertical cross-sectional shape as viewed in the longitudinal direction in the upper portion of the burner space in a state where its longitudinal direction is along the left-right direction. The upper and lower two-stage gas ejection portions 4A, 4B are formed on the forming wall body 2.
And a space inside the ejection part forming wall 2 is used as a combustion space 3. That is, the two mixed gas jetting sections 4A and 4B for jetting the mixed gas supplied from the mixed gas supply section B are juxtaposed in the mixed gas supply direction of the mixed gas supply section B and are jetted into the combustion space 3. Thus, the ejection portion forming wall body 2 is provided in upper and lower two stages. Hereinafter, the mixed gas ejection portion 4A located on the upper side in the mixed gas supply direction will be referred to as a lower mixed gas ejection portion 4A, and the mixed gas ejection portion 4B located on the lower side will be referred to as an upper mixed gas ejection portion 4B.

Next, the ejection portion forming wall 2 will be specifically described. The jetting part forming wall 2 is provided with a mixed gas supply part B.
And a bottom portion 2a provided in a posture orthogonal to or substantially orthogonal to the mixed gas supply direction, and a lower portion extending in a posture in which the bottom portion 2a extends upward from both side edge portions of the bottom portion 2a and is inclined in such a manner that the bottom portion 2a extends upward. The inclined walls 2b, 2b, the lower stepped portions 2c, 2c extending outward from the upper edge portions of the lower inclined wall portions 2b, 2b, and the inclined postures that are separated from the outer edge portions of the lower stepped portions 2c, 2c toward the upper side. The extended upper inclined walls 2d, 2
d and the upper stepped portions 2e, 2e extending outward from the upper edge of each of the upper inclined walls 2d, 2d. The outer edge of each of the upper step portions 2e and 2e is connected to the upper edge of the burner casing 1.

In the bottom portion 2a of the jet forming wall 2,
A plurality of mixed gas ejection holes arranged in a row at equal intervals along the longitudinal direction at positions respectively close to connecting portions of the bottom portion 2a and the lower inclined walls 2b, 2b on both sides. 4v is formed. Also, the lower inclined walls 2b, 2b
A mixed gas ejection hole row 4w is formed at a position close to the connection portion in each of the upper inclined walls 2d and 2d.
6 rows of mixed gas ejection holes, 4f, 4g, 4h,
4i, 4j, 4k are formed in a state where they are arranged side by side in the vertical direction.

The arrangement pitch of the mixed gas ejection holes in the mixed gas ejection hole row 4w is formed to be twice the arrangement pitch of the mixed gas ejection holes in the mixed gas ejection hole row 4v.
Also, the mixed gas ejection hole arrays 4f, 4g, 4h, 4i, 4j,
4k is formed so that the mixed gas ejection holes of the adjacent mixed gas ejection hole rows are staggered in a staggered state. Further, the hole diameter of the mixed gas ejection holes of each mixed gas ejection hole row is, for example, 1.5 m in the mixed gas ejection hole row 4v.
1.2 mm in each of the mixed gas ejection hole rows 4w, 4f, 4g, 4h, and 4i, 1.3 mm in the mixed gas ejection hole row 4j, and 1. mm in the mixed gas ejection hole row 4k.
It is 4 mm.

That is, the lower mixed gas ejection portion 4A is composed of the mixed gas ejection hole rows 4v and 4w on both sides,
Further, the upper mixed gas ejection portion 4B is composed of the mixed gas ejection hole rows 4w, 4f, 4g, 4h, 4i on both sides. Therefore, the lower mixed gas jetting section 4A causes the mixed gas to flow downward from the upper side to the lower side in the mixed gas supply direction.
It is configured so that the flame is ejected along the lower inclined wall 2b to form the flame.

Next, the mixed gas supply section B will be specifically described. A space formed outside the jetting portion forming wall 2 (on the side opposite to the combustion space 3) by the back surface of the jetting portion forming wall 2 and the inner surface of the burner casing 1 is a mixed gas supply portion B. In the mixed gas supply portion B, the partition wall body 5 is provided on the lower side from the connection points of the outer edge portion of the lower step portion 2c and the lower edge portion of the upper inclined wall 2d on the back surface of the ejection portion forming wall body 2. , 5 by extending respectively, the portion facing the lower mixed gas ejection portion 4A and the upper mixed gas ejection portion 4
The partition plate is divided into a portion facing B and a punching plate 6 having a large number of holes is provided at the lower edge of each of the partition walls 5 and 5.

That is, the mixed gas supply section B supplies the mixed gas flowing upward from the mixing section M described later to the lower mixed gas ejection section 4A and the upper mixed gas ejection section 4B, respectively.
Due to the flow rate suppressing action of the punching plate 6, the supply pressure of the mixed gas supplied to the lower mixed gas ejection portion 4A is lower than the supply pressure of the mixed gas supplied to the upper mixed gas ejection portion 4B. There is. Specifically, by appropriately setting the number of holes and the hole diameter of the punching plate 6, the ratio of the supply pressure to the lower mixed gas ejection portion 4A and the supply pressure to the upper mixed gas ejection portion 4B becomes 1: 2. It is done.

Therefore, the ejection velocity of the mixed gas ejected from the lower mixed gas ejection portion 4A is set to the upper mixed gas ejection portion 4B.
By making the flow velocity of the mixed gas ejected from the mixture gas slower than that of the mixed gas, the mixed gas ejected from the lower mixed gas ejection portion 4A can be stably burned without a lift even in the case of a high input with a large mixed gas supply amount. Due to the flame holding effect of the stable combustion flame, the mixed gas ejected from the upper mixed gas ejecting portion 4B having a high ejection velocity can be stably combusted, so that the entire gas burner can be combusted stably. Further, the flame formed in the lower mixed gas jetting section 4A is in a state of being along the lower inclined wall 2b from the upper side to the lower side in the mixed gas supply direction, and the flame is jetted from the upper mixed gas jetting section 4B. Since it comes into contact with the mixed gas immediately after being treated, the flame holding effect can be more effectively exerted.

Therefore, even if a lean mixed gas having a high excess air ratio is used as the mixed gas, stable combustion can be achieved over a wide range of inputs, so that the turndown ratio can be increased and NOx is generated. Can be suppressed.

Next, the mixing section M will be specifically described. The mixing section M is a mixed gas supply section B in the burner space.
In the lower part of the channel, the narrow channel R along the left-right direction
In order to form n substantially at the center when viewed in the longitudinal direction, the elongated narrow flow path forming plates 7 and 7 are attached to the burner casings 1 on both sides in a state of extending in the left-right direction, and In order to form the divided flow paths Rb on both sides, a long flow path separation plate 8 is provided above the narrow flow path formation plate 7 along the left-right direction, and the flow path separation plate. 8 and a punching plate 9 for straightening, which is mounted on the upper side of the plate 8.

A fuel gas ejection pipe 10 for ejecting fuel gas to the mixing portion M is arranged below the fuel gas ejection pipe 10 along the narrow passage Rn. The fuel gas ejection pipe 10 has a large number of fuel gas ejection holes 10a, 10a along its longitudinal direction.
Are formed in rows so as to eject the fuel gas toward the narrow flow path forming plates 7, 7 on both sides.

That is, in the mixing section M, the fuel gas ejected from the fuel gas ejection holes 10a, 10a and the combustion air supplied to the fuel gas from below by the sirocco fan 24 through the air supply section K. Means that mixing is promoted in the process of passing through the narrow flow passage Rn and the divided flow passage Rb, and the meandering flow passage formed by the narrow flow passage Rn and the divided flow passage Rb. Mixing is further promoted by the turbulent action and the longer flow action. So,
The mixing portion M is configured so that the mixed state of the fuel gas and the combustion air in the mixed gas becomes good.

Next, the fuel gas supply device D will be specifically described with reference to FIG. In the following description, the fuel gas ejection pipes provided in the burner spaces on the left and right sides are referred to as 10L and 10R, respectively, in the front view of the burner casing 1 for the sake of clarity.

A proportional valve 14 is interposed in the fuel gas supply pipe 13, and the fuel gas supply pipe 13 is branched into branch pipes 13L and 13R on the lower side of the proportional valve 14 to form a branch pipe 13.
L is connected to the fuel gas ejection pipe 10L, and the branch pipe 13R is connected to the fuel gas ejection pipe 10R, and the branch pipe 13L is provided with an opening / closing valve 15 to form a fuel gas supply device D. The proportional valve 14 and the on-off valve 15 are controlled by the control block S.
It is provided inside.

Next, the NOx sensor N1 will be specifically described with reference to FIGS. 6 and 7. NOx sensor N1
Is an agglomerated gas detection part 3 made of a composite oxide on the upper side of a heating substrate 31 made of a ceramic heater plate.
2, a pair of Pt current applying electrodes 33 for the gas detection unit 32 and P for the current applying electrodes 33 are provided.
The t voltage detection electrode 34 is provided. With the NOx sensor N1 thus configured provided in a casing (not shown) through which gas can freely pass, the air suction port 22b is provided.
It is provided in. The main component of the gas detector 32 is

Embedded image (X is 0 or more and less than 1 and δ is 0 or more and 1 or less), and the crystal structure is constituted by so-called BSCCO 2212 single phase, and has semiconductivity. Since the electric resistance value of the gas detection unit 32 changes according to the nitrogen oxide concentration in the air,
The nitrogen oxide concentration in the air is detected based on the detection of this resistance value.

Next, the resistance value of the gas detector 32 is detected.
The method will be described. Applying a constant voltage to the heating substrate 31
Then, the gas detector 32 is set to a predetermined temperature (for example, 350 ° C.).
C) and a predetermined current (for example, 1
0 mA) and measure the voltage with the voltage detection electrode 34
Then, the resistance value is obtained. The gas detector 32 has been changed to the above chemical formula 1.
And is composed of a composite oxide of x = 0.8 and 35
NO gas and NO when heated at 0 ° C₂Each gas
FIG. 7 shows the sensitivity characteristic with respect to. In the figure, nitrogen oxide
The resistance value in the air that does not contain R₀(Ω), nitrogen oxide
The resistance value in air containing is indicated by R (Ω). Incidentally, the real
In the air in the room to be heated at this time, NO
Gas and NO₂Gas is included, but gas detector
The resistance value change of 32 is NO gas and NO. ₂By each gas
It appears in the state that the change in resistance value is added.

Next, the control configuration of the controller C will be described with reference to FIG. The control device C has a NOx sensor N
1, a temperature sensor T, a heating target temperature setting device 40 provided on an operation panel (not shown), a sirocco fan 24, a proportional valve 14 and an on-off valve 15, are connected, and the control device C is connected to the NOx sensor N.
1, the sirocco fan 24, the proportional valve 14, and the on-off valve 15 are controlled based on the detection information of the temperature sensor T and the target temperature information from the heating target temperature setter 40.

First, a control configuration for maintaining the room temperature of the room to be heated at the target temperature set by the heating target temperature setting device 40 will be described. Based on the temperature detected by the temperature sensor T and the target temperature set by the heating target temperature setting unit 40, the combustion amount of the gas burner G (hereinafter referred to as input) is obtained. Then, when the obtained input is from the maximum value to 1/3 of the maximum value, the open / close valve 15 is opened,
A proportional valve is provided so that the fuel gas is supplied to the left and right mixing parts M, M and is burned in the left and right burner parts A, A so that the fuel gas supply amount (Ig) corresponds to the obtained input. Adjust the opening of 14. When the calculated input is from the minimum value to less than 1/3 of the maximum value, the on-off valve 15 is closed, the fuel gas supply to the left mixing section M is stopped, and the fuel gas is supplied only to the right mixing section M. The opening of the proportional valve 14 is adjusted so that the fuel gas supply amount (Ig) corresponding to the obtained input is obtained in the state where the fuel gas is supplied and burned in the right burner portion A.

Further, the sirocco fan 24 is controlled so that the combustion air supply amount (Ia) according to the input is obtained. The mixed gas supplied to the burner portion A is a lean mixed gas having an excess air ratio of 1.4 to 1.7.

Next, based on the detection information of the NOx sensor N1, the air-fuel ratio (combustion air supply amount (Ia) and fuel gas supply amount (Ig) (Ia / I) for the gas burner G is calculated.
A control configuration for controlling g)) will be described. The control device C applies a constant voltage to the heating substrate 31 of the NOx sensor N1, applies a predetermined current to the current-flowing electrode 33, measures the voltage with the voltage detection electrode 34, obtains a resistance value, and then determines the resistance value. Determine the nitrogen oxide concentration by.
Then, when the obtained nitrogen oxide concentration becomes larger than the preset allowable set value, the fuel gas supply amount (Ig) becomes a predetermined value (for example, 30% or more) than the value corresponding to the input at that time.
%), The air-fuel ratio (Ia / Ig) is increased by controlling the on-off valve 15 and the proportional valve 14 so as to decrease. Subsequently, the air-fuel ratio (Ia / Ig) continues to be increased until the calculated nitrogen oxide concentration becomes smaller than the allowable set value by a predetermined value (for example, 10%). When the predetermined value is smaller than the allowable set value, the input at that time is obtained, and the on-off valve 15 and the proportional valve 14 are controlled so that the fuel gas supply amount (Ig) according to the input is obtained. By repeating such control, the nitrogen oxide concentration in the room to be heated is maintained below the allowable set value.

Therefore, using the control device C, the air-fuel ratio (Ia / Ig) is calculated based on the detection information of the NOx sensor N1.
The air-fuel ratio adjusting means C1 for adjusting Further, the on-off valve 15 and the proportional valve 14 function as fuel supply amount adjusting means for adjusting the fuel gas supply amount (Ig) to the burner G.

Another Embodiment Next, another embodiment will be described. In the above embodiment, the NOx sensor N1 is provided at the air suction port 22b in order to detect the concentration of nitrogen oxides in the air in the heating target room sucked through the air suction ports 22a, 22b. The installation position of the NOx sensor N1 provided for detecting the concentration of nitrogen oxides in the air of the room to be heated sucked in from can be variously changed.
For example, it may be provided in the air suction port 22a, the casing 23, the air supply portion K of the gas burner G, or the like.

In the above embodiment, the nitrogen oxide sensor N
The NOx sensor N1 as the air intake ports 22a, 22
Although it was provided so as to detect the nitrogen oxide concentration in the air of the room to be heated sucked from b, the nitrogen oxide sensor N was in the combustion gas produced by the gas burner G or in the air-fuel mixture discharged from the hot air outlet 21. May be provided so as to detect the concentration of nitrogen oxides. The permissible set values are for the case of detecting the nitrogen oxide concentration in the combustion gas generated from the gas burner G and the case of detecting the nitrogen oxide concentration in the air-fuel mixture discharged from the hot air outlet 21. Set separately. When detecting the nitrogen oxide concentration in the produced combustion gas, as shown by a broken line in FIG. 1, a NOx sensor N2 as the nitrogen oxide sensor N is provided in the combustion gas passage P of the gas burner G, for example. Set up. Further, when detecting the nitrogen oxide concentration in the air-fuel mixture, NOx as the nitrogen oxide sensor N is indicated by the broken line in FIG.
The sensor N3 is provided, for example, at the hot air outlet 21. However,
When the NOx sensor N2 is provided in, for example, the combustion gas flow path P, the NOx sensor N2 is exposed to a high-concentration nitrogen oxide atmosphere and a high-temperature atmosphere, and therefore has a drawback of rapid deterioration.

In the above embodiment, the air-fuel ratio adjusting means C1
The above is an example of a case where the air-fuel ratio (Ia / Ig) is adjusted to a large value based on controlling the on-off valve 15 and the proportional valve 14 so that the fuel gas supply amount (Ig) is reduced. Instead of this, the sirocco fan 24 is controlled so that the combustion air supply amount (Ia) to the burner G is increased.
The air-fuel ratio (Ia / I
It may be configured to adjust g) to a large degree. Further, the decrease amount of the combustion air supply amount (Ia) is the fuel gas supply amount (Ig)
Of the combustion air supply amount (I
Both a) and the fuel gas supply amount (Ig) may be reduced, and the air-fuel ratio (Ia / Ig) may be adjusted to a large value.

In the above embodiment, the air-fuel ratio adjusting means C1
The above is an example of the case where the air-fuel ratio (Ia / Ig) is adjusted so that the detected nitrogen oxide concentration of the nitrogen oxide sensor N is maintained at the allowable set value or less. The air-fuel ratio (Ia / Ig) may be adjusted so that the concentration of nitrogen oxides detected by the oxide sensor N is maintained below a set value determined according to the input of the gas burner G. The set value may be set to be large in proportion to the input, as shown in FIG.
Alternatively, as shown in FIG. 9B, the input is divided into a plurality of stages and each divided stage is set.
In this case, it is preferable to adjust the air-fuel ratio (Ia / Ig) by knowing the state of generation of nitrogen oxides from the gas burner G. Therefore, as shown by the broken line in FIG. The NOx sensor N2 as the gas burner G
The NOx sensor N3 is provided in the combustion gas flow path P so as to detect the nitrogen oxide concentration in the generated combustion gas by, or the NOx sensor N3 detects the nitrogen oxide concentration in the air-fuel mixture discharged from the hot air outlet 21. As described above, it is preferable to provide the hot air outlet 21.

As the nitrogen oxide sensor N, various ones other than the NOx sensor N1 exemplified in the above embodiment can be used. For example, a semiconductor sensor such as SnO ₂ or ZnO, a solid electrolyte sensor, an electrochemical sensor, or the like can be used.

The NOx sensor N1 shown in the above embodiment
In addition to the above, a CO sensor for detecting the concentration of CO gas in the air in the room to be heated is provided, and the air-fuel ratio (Ia / Ig) for the gas burner G is adjusted based on the detection information of the CO sensor, The CO concentration in the air in the chamber may also be maintained in an appropriate state.

Various burners other than the gas burner G exemplified in the above embodiment can be used. Further, in the above embodiment, the case where the gas burner G using the fuel gas as the fuel is used has been exemplified, but a burner using the liquid fuel as the fuel may be used.

In addition to the sirocco fan 24 exemplified in the above embodiment, various ventilation means can be used.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

[Fig. 1] Vertical left side view of the hot air heater

[Fig. 2] A vertical sectional front view of the warm air heater

FIG. 3 is a perspective view of a gas burner of a warm air heater.

FIG. 4 is a vertical sectional side view of the gas burner of the warm air heater.

FIG. 5 is a vertical sectional front view of the gas burner of the warm air heater.

FIG. 6 is a diagram showing a configuration of a NOx sensor of a warm air heater.

FIG. 7 is a diagram showing sensitivity characteristics of a NOx sensor of a warm air heater.

FIG. 8 is a block diagram of a control configuration of a warm air heater.

FIG. 9 is a diagram showing a relationship between a burner combustion amount and a set value in another embodiment.

[Explanation of symbols]

 14, 15 Fuel supply amount adjusting means 21 Air outlets 22a, 22b Suction opening 24 Ventilation means C1 Air-fuel ratio adjusting means G Burner N Nitrogen oxide sensor

Claims (6)

[Claims] 1. A burner (G) and the burner (G), wherein a part of the air in the heating target room sucked from the suction ports (22a), (22b) is used as combustion air.
Ventilation means (24) for supplying the air to the heating target chamber and blowing the mixture to the heating target chamber by mixing the rest with the combustion gas generated by the burner (G) and blowing the mixture from the air outlet (21).
A warm air heater provided with, in the air of the room to be heated, or in the generated combustion gas,
Alternatively, based on the nitrogen oxide sensor (N) that detects the nitrogen oxide concentration in the air-fuel mixture, and the detection information of the nitrogen oxide sensor (N), the combustion air supply amount to the burner (G) ( A hot-air heater provided with an air-fuel ratio adjusting means (C1) for adjusting an air-fuel ratio indicating a ratio (Ia / Ig) between Ia) and a fuel supply amount (Ig). 2. The air-fuel ratio adjusting means (C1) adjusts the air-fuel ratio based on the detection information of the nitrogen oxide sensor (N) so as to maintain the nitrogen oxide concentration below an allowable set value. The warm air heater according to claim 1, which is configured to: 3. The air-fuel ratio adjusting means (C1) determines the nitrogen oxide concentration according to the combustion amount of the burner (G) based on the detection information of the nitrogen oxide sensor (N). The warm air heater according to claim 1, wherein the air-fuel ratio is adjusted so as to be maintained below a set value. 4. Fuel supply amount adjusting means (14), (15) for adjusting the fuel supply amount to the burner (G) are provided, and the air-fuel ratio adjusting means (C1) is the fuel supply amount adjusting means. The warm air heater according to claim 1, 2 or 3, which is configured to adjust the air-fuel ratio based on controlling (14) and (15). 5. The air-fuel ratio adjusting means (C1) is configured to adjust the air-fuel ratio on the basis of controlling a ventilation amount of the ventilation means (24).
Or the warm air heater described in 3. 6. The nitrogen oxide sensor (N) is provided in the main body so as to detect the nitrogen oxide concentration in the air sucked from the suction ports (22a), (22b). The hot air heater according to 2, 3, 4 or 5.